Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 498 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.⚡ A 48 W device works on 24 V. What current does it take (in amperes)? =
2. 2.Which job needs a light sensor? (a) open blinds at sunrise (b) close a window in rain (c) measure classroom noise (d) stop a robot near walls
3. 3.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
4. 4.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 50 ms }
   How many times does the LED blink in 3 seconds?
5. 5.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 1000 (c) 100 (d) 60
6. 6.Which of these usually has a microcontroller inside? (a) a candle (b) a wind-up toy (c) a spinning top (d) a microwave oven
7. 7.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
8. 8.True or false: a microcontroller needs much more power. (a) True (b) False
9. 9.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 120 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
10. 10.🔋 How many 3 V cells must be joined in series to give 18 V?
11. 11.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
12. 12.Which of these mainly gives out light? (a) an electric iron (b) a mixer grinder (c) a tube light (d) a ceiling fan
13. 13.⚠️ Is it safe to climb an electric pole? (a) safe (b) not safe
14. 14.Which of these is not safe? (a) stop if a part gets hot (b) stay away from pylons (c) dry your hands first (d) use mains for a project
15. 15.True or false: an LED lamp mainly gives out light. (a) False (b) True
16. 16.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
17. 17.🔢 To plan an electronics project, what comes right after “draw the circuit diagram”? (a) list inputs and outputs (b) pick a problem to solve (c) test it and fix it (d) build it with an adult
18. 18.🧩 Which component makes things spin? (a) motor (b) buzzer (c) capacitor (d) resistor
19. 19.🗺️ In an input → process → output plan, is “an alert on the phone” the input, the process or the output? (a) input (b) process (c) output
20. 20.🔋 How many 1.5 V cells must be joined in series to give 4.5 V?
21. 21.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 6 hours?
22. 22.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
23. 23.True or false: the ammeter is joined across a part. (a) False (b) True
24. 24.🧮 A 4.5 V battery is joined to 3 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
25. 25.🔍 Which is the odd one out? (a) a water heater (b) an electric drill (c) a ceiling fan (d) a table fan
26. 26.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
27. 27.🔋 What should you do with used-up cells? (a) throw them in a fire (b) give them for recycling (c) cut them open (d) bury them in soil
28. 28.True or false: to dry your hands first is safe. (a) True (b) False
29. 29.Which drawing is the symbol for a switch? (a) a circle with V inside (b) a line lifted at a gap (c) a circle with a cross (d) triangle against a bar
30. 30.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to limit the current (c) to change its colour (d) to store charge
31. 31.🔁 total = 0
    for i = 1 to 5 { total = total + i }
    What is total at the end?
32. 32.🤖 Microcontroller or laptop: which one runs one small program? (a) laptop (b) microcontroller
33. 33.Which of these is true of a series circuit? (a) one out, the rest glow (b) a single current path (c) each gets the full volts (d) used in house wiring
34. 34.🔌 Is a ceramic cup a conductor or an insulator? (a) an insulator (b) a conductor
35. 35.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
36. 36.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the plastic handle (c) the steel shaft (d) the bare end
37. 37.Which of these is a good habit? (a) keep factory passwords (b) turn off unused gadgets (c) share camera links (d) reuse one password
38. 38.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) a cell is taken out (d) the switch is ON
39. 39.Which of these is measured in ohms (Ω)? (a) energy used each second (b) voltage (c) how much a part resists (d) the flow of charge
40. 40.🔁 count = 0
    repeat 3 times { count = count + 4 }
    What is count at the end?

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